There is known a centrifuge (cf., a pamphlet of the Beckman Company "Preparation Ultracentrifuge", L 8, p. 5) comprising a vacuum chamber, a drive of a replaceable rotor, a diffusion pump, a refrigeration system, and a system for cooling the drive and diffusion pump. In this centrifuge, the temperature conditions of the drive of the replaceable rotor are maintained by an additional cooling unit built into the centrifuge. Such an arrangement structurally over-complicates the centrifuge, since it requires the provision of two cooling units, viz., one in the refrigeration system of the vacuum chamber, and one in the cooling system of the drive.
There is also known a centrifuge (cf., materials of the Symposium "Laboratory Centrifuge and Ultracentrifuges of the `Heraeus Christ` Company", pp. 4 to 6) comprising a vacuum chamber, a drive of a replaceable rotor, a diffusion pump, a refrigeration system, a system for lubricating the drive bearings, and a cooling system. In this centrifuge, the temperature conditions of the replaceable rotor are maintained by the refrigeration system, whereas the temperature conditions of the drive of the replaceable rotor and diffusion pump--by a cooling system in which water from a water main line is used as a cooling agent. This, in turn, makes the system less mobile, necessitates additional pipes for feeding and discharging water, filters and special fixtures. Another disadvantage is associated with periodic cleaning of the pipes, filters and passages. In addition, water discharged from the centrifuge is not fit for reuse, which is very disadvantageous both from the economic and ecological points of view.
There is also known a modification of the aforedescribed construction (cf., materials of aforesaid Symposium, p. 15) comprising a vacuum chamber accommodating a replaceable rotor, a cooling unit connected via a line circulating a cooling agent to an evaporator disposed inside said chamber, a drive of the replaceable rotor having bearings and a cooling jacket, and an oil tank with a pump for feeding oil to the bearings. Cooling of the rotor drive and diffusion pump is done in this centrifuge construction by a special electrical means for circulating water.
This arrangement is rather complicated, since it necessitates an additional water tank, a pump for circulating the water, a heat exchanger and a second cooling unit. An accompanying disadvantage is excessive weight and size of the centrifuge.